Final answer:
In management by exception, variable overhead efficiency does not usually affect the production manager who is typically focused on direct materials efficiency, direct labor cost, and direct labor efficiency.
Step-by-step explanation:
When using management by exception, the variance that would not typically affect the production manager is variable overhead efficiency. The production manager is usually concerned with variances related to direct labor and materials. This includes direct materials efficiency, direct labor cost, and direct labor efficiency as they pertain to the actual usage and cost of inputs for the products being manufactured. Variable overhead is often related to broader operational issues and not tied to specific production activities, making it less likely to be under the direct control of the production manager.